Kinetics of Cell Volume Changes of Murine Lymphoma Cells Subjected to Different Agents In Vitro

Cell volume distributions obtained with an electronic particle analyzer were used to study the changes in volume of individual cells in the absence of cell division. Cultures of murine lymphoma (strain L5178-Y) cells in suspension were used in these studies. During a division delay following ionizing radiation, individual cells increased exponentially in volume with equal rate constants; these rate constants were indistinguishable from that describing the increase in cell number of an unirradiated population. When an originally log phase population of cells was prevented from increasing in number by inhibitors of DNA synthesis, individual cells increased exponentially in volume for about one generation time with the same rate constant as observed after exposure to ionizing radiation; thereafter, only the cells defining the upper half of the volume distribution continued to increase in volume, and they apparently did so with a first order rate constant proportional to their amount of DNA exceeding that present in one diploid complement of chromosomes in G 1 . Cells arrested in mitosis with colchicine increased in volume for approximately 4 hr after which they remained constant in volume for almost one generation time; eventually these cells again increased in size. Inhibitors of protein and RNA synthesis inhibited the cell volume growth of irradiated cells.